In this article, Dialogical sequence analysis (DSA) is introduced as a method in theory-based single case research. The structure of article is as follows: first, we will describe briefly the historical background of single case studies and their position as the foundation of psychoanalytic knowledge formation. Secondly, we will describe through Amalia X’s case how one psychoanalytic ‘specimen case’ has been used as a cornerstone for a comprehensive psychoanalytic process research model, the so called ‘Ulm model’. Amalia X is one of the most studied single cases internationally also outside psychoanalytic process study field. Thirdly, we will introduce the central theory and practice of DSA. Fourthly, in the last section of our article, we will show in practice how DSA can be used in the analysis of Amalia’s dream in the session 152.